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A preliminary study of the structure, stratigraphy and metamorphism of some contact rocks of the western Andes, near the Quebrada Venado Muerto, Peru
Author(s) -
Atherton M. P.,
Brenchley P. J.
Publication year - 1972
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350080114
Subject(s) - hornblende , geology , metamorphic rock , metamorphism , geochemistry , pluton , volcanic rock , stratigraphy , mineral , volcano , paleontology , biotite , tectonics , quartz , materials science , metallurgy
The sequence and structure of the volcanic rocks of a small area lying within the main belt of plutons of the Peruvian Andes were mapped and are here described. Metamorphic zoning of the calcareous aureole minerals was shown to be similar to that described elsewhere, e.g. wollastonite, diopside, hornblende with increasing distance from the contact. The mineral assemblages and their spatial and textural character indicate rapid heating of the aureole, with only a short time at maximum temperatures. The complex mineralogy in individual rocks is interpreted in terms of changing physical conditions during the thermal event. The sequential assemblages are the result of changes in activity of CO 2 , H 2 O and Fe 3+ in particular.